Two years after Roy Keane's departure, Anderson put in a performance at the Emirates that suggested Manchester United had uncovered a feisty midfielder with the niggle and bite the talismanic Irishman had supplied for 12 years.

That 2007-08 campaign now goes down as the Brazilian's most successful season of a disappointing seven years at Old Trafford, which may end with him leaving for Fiorentina before the transfer window closes. Anderson has become the emblem of the scarcely credible agonies Sir Alex Ferguson and David Moyes have suffered trying to restock the midfield of one of the world's richest clubs since Keane departed in 2005.

Not 26 until April, the Brazilian was by now supposed to be the mainstay of the champions' engine room, the fixture on the team-sheet who could destroy attacks and search out a killer pass ahead of a 60-yard gut-bursting run to finish what he had began.

That debut season ended with Anderson recording 24 Premier League appearances, of which 16 were starts. Both are career-high numbers for United, as is the total of 38 times he played for the club in all competitions during a campaign that ended in an 119th-minute entrance into United's Champions League final against Chelsea in Moscow. Anderson took the sixth penalty in a shootout that made him a European champion at only 20 years of age.

Anderson had been signed the previous summer after two seasons with Porto, Ferguson convinced by a glowing endorsement from his brother, Martin. In his recent book, the former manager recalled: "Martin said: 'Alex, he's better than Rooney.'"

As Ferguson observed, this was some accolade. Anderson, who won the Golden Ball as the best player of the 2005 Under-17s World Cup, has never come close to showing he deserved it.

The years of perennial disappointment have seen him chalk up only 70 league starts, five goals and seven assists, a return that is paltry for any box-to-box midfielder, which is what Anderson was billed as when he arrived and what he appeared to be during that draw at the Emirates. Instead, the jibes about his weight and the stuck-on-repeat insistence that the next campaign would be career-defining is what he will be remembered for.

In September, yet again, Anderson said: "I think it's a big season for me. However, I don't want to say that and then pick up another injury. I have often started seasons well, played six or seven games and then got injured. I'll tell you at the end of the season if it's been a big season for me."

Just two months later, he was saying: "Every player wants to play every game. I am the same. I am only 25 years old, but I cannot stay one more year and not play. I need to play. But you cannot demand to play, you have to be patient and when you get your chance you have to do well. The club have always been nice to me and I am happy here, but if I have to go eventually then I have to go. But I will do my best for United."

United may have been kind, handing him a fresh four-and-a-half-year contract in 2010, but the dressing room's unforgiving arena has offered a crueller truth, which has come wrapped in players' humour. In Rio Ferdinand's pre-season tour diary of last summer, the defender and Patrice Evra joked about Anderson's appetite and how the left-back would deliver burgers for him to eat.

Now, Fiorentina say that they are interested in a footballer who is out of contract in the summer of 2015. Daniele Pradè, the Italian club's sporting director, said: "Anderson is a player who Fiorentina likes and is following, but this certainly applies to many other players."

This year there have been eight appearances, the last coming a month ago in a 2-0 win at Stoke City in the Capital One Cup. That was a rare start but it was in the least of the four competitions United challenge for each year.

In the big time of Premier League football, Moyes has named Anderson only twice in his starting XI and he may depart stuck on a total of 104 appearances in the top flight. In his 70 starts Anderson was substituted a staggering 51 times, meaning he completed only 19 matches: this is around two and a half full games for each of the seven years at the club – one of a plethora of statistics that illustrate why United are willing to move him on.